Patent Grant
8444784
The present invention generally relates to explosive compositions and methods for fabricating explosive compositions and, more particularly, relates to insensitive munition-type BNCP explosive material and methods for synthesizing insensitive munition-type BNCP explosive material.
Historically, azide-based primary explosives, namely lead azide and lead styphnate, were utilized in electroexplosive devices and mechanically-actuated devices as viable primary explosives, replacing toxic lead picrate and mercury fulminate, which had unpredictable shelf-lives. Over the years, however, extensive and long-term use of lead azide and lead styphnate in primary explosives has resulted in significant lead contamination of artillery and firing ranges, and has caused major health hazards and environmental problems for both military and civilian personnel.
Bis, nitro cobalt (III) perchlorate, or using the IUPAC convention, cis-bis-(5-nitrotetrazolato)tetramine cobalt (III) perchlorate (hereinafter “BNCP”), is a primary explosive that does not contain lead and thus has become an alternative to the lead-comprising explosives. BNCP undergoes deflagration-detonation transition (DDT) in very short distances and maintains energetic properties similar to lead azide and lead styphnate upon exposure to the atmosphere. In addition, BNCP is insensitive to light, is thermally stable to at least 200° C., is chemically stable for extended periods, and is absent of any and all lead-based-type toxic metals, such as mercury, silver, barium, and antimony. However, conventional BNCP is sensitive to handling and transportation, which renders it susceptible to sympathetic detonation as a result of mechanical shocks, fire, electrostatic discharge, and impact by shrapnel. A desirable BNCP explosive material would conform to “insensitive munition” (IM) properties, that is, properties that would render it capable of withstanding sympathetic detonation as a result of mechanical shocks, fire, electrostatic discharge, and impact by shrapnel, yet still be capable of high-order detonation per design intent.
Accordingly, it is desirable to provide an insensitive munition-type BNCP explosive material. In addition, it is desirable to methods for synthesizing insensitive munition-type BNCP explosive material. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.
Insensitive munition-type explosive material and methods for forming insensitive munition-type explosive material are provided. In an exemplary embodiment, an insensitive munition-type explosive material comprises a particle of BNCP and a surfactant-comprising shell that encapsulates the particle of BNCP.
In accordance with an exemplary embodiment, a method for forming an insensitive munition-type BNCP explosive material comprises combining NaNT, CTCN, and perchloric acid to form a mixture, forming a BNCP precipitate from the mixture, collecting the BNCP precipitate, and forming an insensitive munition-type BNCP in an emulsion from the BNCP precipitate and a surfactant.
In accordance with another exemplary embodiment, a method for forming an insensitive munition-type BNCP explosive material comprises dispersing BNCP and a surfactant in a liquid phase to form an emulsion comprising IM BNCP, filtering the emulsion to collect the IM BNCP, and drying the IM BNCP.
The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and wherein:
The following detailed description of the invention is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background of the invention or the following detailed description of the invention.
The various embodiments contemplated herein relate to BNCP explosive material that exhibits improved IM properties compared to conventional BNCP. In particular, various embodiments contemplated herein are directed to an insensitive munition-type explosive material comprising a particle of BNCP encapsulated by a surface active agent or “surfactant”. The surfactant serves as a protective/desensitizing shell that protects the BNCP particle from mechanical shocks, fire, electrostatic discharge, and impact by shrapnel that would otherwise result in sympathetic detonation of the BNCP. Despite the presence of the surfactant shell, however, the BNCP particle is still capable of high-order detonation per design intent.
Referring to
Surfactants 14 suitable for use in the IM BNCP include anionic, nonionic, cationic, and amphoteric surfactants, and combinations thereof. Any surfactant that can be added to a selected liquid phase to lower the surface tension of the selected liquid phase sufficiently so that BNCP particles 12 can form a colloidal dispersion, i.e., an emulsion, with the selected liquid phase can be used. For example, if water is the selected liquid phase, sodium laurel sulfate can be used as a surfactant to suspend BNCP particles in the water, thus forming a colloidal dispersion or an emulsion. Examples of anionic surfactants suitable for use in the exemplary embodiments of the IM BNCP contemplated herein include ammonium dodecyl sulfate, sodium lauryl sulfate, perfluorobutanesulfonic acid, sodium bis(2-ethylhexyl) sulfosuccinate, sodium lauroyl sarcosinate, sodium tallowate, and the like.
Examples of nonionic surfactants suitable for use include polyoxy-ethylene alcohols, alkyl phenol ethoxylates, sorbitan monopalmitate, methyltrialkyl(C8-C10)ammonium chlorides, such as Adogen® 464 manufactured by Sherex Chemical Company of Mapleton, Ill., the Brij® class of nonionic surfactants, including, but not limited to, Brij® 30, Brij® 52, Brij® 56, Brij® 58, Brij® 72, Brij® 78, and Brij®92V (the Brij® class manufactured by Croda International, United Kingdom), Alkonal® from E.I. du Pont de Nemours & Company, Wilmington, Del., the Igepal® class of nonionic surfactants, including, but not limited to, Igepal® CA-210, Igepal® CA-520, Igepal® CA-720, Igepal® CO-210, Igepal® CO-520, Igepal® CO-630, and Igepal® CO-720 (the Igepal® class manufactured by Rhodia Novecare of Cranbury, N.J.), the Merpol® class of nonionic surfactants, including, but not limited to, Merpol® A, Merpol® DA, Merpol® OJ, Merpol® SE, and Merpol® SH (the Merpol® class manufactured by Stepan Company of Northfield, Ill.), Triton®N-101 and Triton® X-114 manufactured by Dow Chemical Company of Midland, Mich., Tween® 20 manufactured by Roche Applied Science of Germany, and the Zonyl® class of nonionic surfactants, including, but not limited to, Zonyl® FS-300, Zonyl® FSA, Zonyl® FSE, Zonyl® FSJ, Zonyl® FSK, Zonyl® FSN, and Zonyl® FSO (the Zonyl® class manufactured by E.I. du Pont de Nemours & Company, Wilmington, Del.).
Examples of cationic surfactants suitable for use in the exemplary embodiments contemplated herein include quaternary ammonium salts. Amphoteric surfactants also suitable for use herein include long chain ethers, fatty acid esters, amides, and carboxybetaines.
A method 30 of forming an IM BNCP, in accordance with an exemplary embodiment, is illustrated in
In one optional embodiment (not shown), the resulting emulsion can be used for the ignition of liquid propellants, such as, for example, ignition of hydroxylammonium nitrate (HAN) liquid propellant. In another optional embodiment, the resulting emulsion is filtered, such as by vacuum-filtration, to collect the IM BNCP from the remaining mixture (step 34). The IM BNCP then can be air-dried and/or oven-dried (step 36) and packaged or tested as desired. Because the BNCP is insensitive, it imparts characteristics that make it attractive for use not only as an ignition material, but also as a very high output IM explosive for warheads.
In one exemplary embodiment, the step 32 of dispersing the surfactant followed by the dispersion of the BNCP in a liquid phase includes pre-forming BNCP and then dispersing the pre-formed BNCP and a surfactant in the liquid phase to form IM BNCP. Referring to
In a preferred exemplary embodiment, the step of forming a BNCP precipitate (step 104) comprises forming subsequently smaller diameter micron sizes of BNCP particles before fine BNCP particles are encapsulated by the surfactant. As noted above, BNCP is an ignition material that undergoes deflagration-detonation transition (DDT). The smaller the particle size of the BNCP, the higher the surface area of the BNCP and the more efficient the DDT process is. Additionally, time to ignition and time to achieve maximum pressure of an igniter must be reproducible, must be accurate, and must occur very rapidly; this is achieved when the mass burning rate of the ignition material is markedly quick. Particle size of the ignition material controls relative quickness (Rq) to DDT of the ignition material and, thus, small particle diameter size is preferred. In this preferred method, illustrated in
A more preferred embodiment of steps 102, 104, 106, and 108 of
Next, recrystallization of the crude BNCP is performed to produce a distribution of smaller size BNCP particles (step 112 of
Fine BNCP then is formed to achieve BNCP particles having a particle diameter size in the range of about 20 nm to about 8 μm (step 114 of
In one exemplary embodiment, the step of forming IM BNCP (step 108) begins by creating a low surface tension medium with the formation of a surfactant-liquid phase solution (step 150). In this regard, a liquid phase, such as for example, isopropyl alcohol, deionized water, polyethylene glycol, polypropylene glycol, or the like, and a suitable surfactant are combined using vigorous mixing, such as vigorous stirring, shaking, agitation, FEM, etc., for homogenization. In a preferred embodiment, the liquid phase is cooled to a temperature in the range of about 1.7° C. (35° F.) to about 18.3° C. (65° F.), preferably about 10° C. (50° F.), before the surfactant is added. Once the surfactant is completely dispersed in the solution phase, the stirring is slowed and the fine BNCP is slowly added to the solution (step 152). When all of the fine BNCP is added, the solution is heated to a temperature in the range of 71° C. (160° F.) to about 88° C. (190° F.), preferably about 79° C. (175° F.), while vigorous stirring is again performed (step 154). Stirring is continued for about 15 seconds to about a minute, preferably about 30 seconds, and then the solution is cooled to about −3.8° C. (25° F.) to about 1.7° C. (35° F.), preferably about 0.6° C. (31° F.) (step 156). After the completion of step 108 of
In an alternative exemplary embodiment to those depicted in
Next, the emulsion is heated to an elevated temperature in the range of 71° C. (160° F.) to about 88° C. (190° F.), preferably about 79° C. (175° F.), while moderate stirring is performed (step 178). The emulsion can be maintained at a pH of about 2-3 with the addition of perchloric acid as needed. The elevated temperature is maintained for about 15 minutes to about an hour, preferably about 30 minutes. The emulsion is cooled to about 40° C. (105° F.) to about 57° C. (135° F.), preferably about 49° C. (120° F.) and then is chilled to about −7° C. (18° F.) to about −2° C. (28° F.), preferably about −5° C. (23° F.) (step 180). The emulsion can be chilled by placing a beaker or other vessel of the emulsion in an ice bath or by pouring the emulsion into a chilled liquid, such as, for example, isopropyl alcohol. The emulsion is chilled for about from thirty minutes to about 2 hours, preferably about one hour, at which time IM BNCP precipitate forms. Referring back to
The following are exemplary embodiments of methods for forming IM BNCP as contemplated herein. The examples are provided for illustration purposes only and are not meant to limit the various embodiments of the methods in any way.
In a 250 milliliter (ml) beaker, 16.8 grams (g) of NaNT was dissolved in 100 ml deionized water. To the solution, about 0.1 g of 70% perchloric acid was added until the pH of the solution was about 2 to about 3. The solution was stirred and, during stirring, 10 g of CTCN was added to the solution. 70% perchloric acid was added drop-wise to the solution until the pH of the solution returned to 2 to about 3. During this procedure, CO2 gas evolved. Stirring was continued and the solution was heated to about 90.5° C. (195° F.) while the pH was maintained at about 2-3 by the addition of perchloric acid as needed. The solution temperature was maintained at 90.5° C. (195° F.) and a pH of about 2-3 for about 2.5 hours. The solution was cooled to about 48.8° C. (120° F.) and the beaker was placed in an ice bath to cool the solution to −0.5° C. (31° F.). The solution remained at this temperature for one hour during which a crude BNCP precipitate formed. Vacuum filtration was performed to remove the crude BNCP precipitate from the emulsion and the precipitate particles were washed with cold de-ionized water. The precipitate was then washed with isopropyl alcohol and air dried.
In a 2000 ml beaker, 2 ml of 70% perchloric acid was added to 1000 ml de-ionized water to produce a 0.2% perchloric acid solution. For each 20 ml of the 0.2% perchloric acid solution, one gram of the crude BNCP precipitate was dissolved therein. The solution was heated to about 90.5° C. (195° F.) and stirred until the crude BNCP was substantially completely dissolved and the solution was clear. The solution was removed from the heat and cooled to about 48.8° C. (120° F.) with stirring. The solution then was chilled to −0.5° C. (31° F.). The solution remained at this temperature for one hour during which a recrystallized BNCP precipitate formed. Vacuum filtration was performed to remove the recrystallized BNCP precipitate from the emulsion and the precipitate particles were washed with isopropyl alcohol and air dried.
The recrystallized BNCP was dissolved in 0.2% perchloric acid solution in a ratio of 1 g recrystallized BNCP per 20 ml 0.2% perchloric acid solution. The solution was heated to about 90.5° C. (195° F.) and was stirred until the recrystallized BNCP was substantially completely dissolved and the solution was clear. The solution was removed from the heat and cooled to about 48.8° C. (120° F.) with stirring. Isopropyl alcohol, in the amount of seven times the volume of the 0.2% perchloric acid in the solution, was chilled to −0.5° C. (31° F.). Once the cooled BNCP solution was clear, it was poured slowly into the chilled isopropyl alcohol and remained at this temperature for one hour during which a bright yellow fine BNCP precipitate formed. Vacuum filtration was performed to remove the fine BNCP precipitate from the solution. The precipitate was then washed with isopropyl alcohol and air dried.
In a 1000 ml beaker containing 500 ml of isopropyl alcohol, 0.05 g of Triton® N-101 was added while stirring at low speed was performed. The temperature was slowly raised to 60° C. (140° F.). 10 g of fine BNCP was slowly added while the emulsion was homogenizing. Once all of the fine BNCP was added, the temperature of the emulsion was raised to 79.4° C. (175° F.) and homogenization was continued for 5 minutes. The dispersion then was chilled to −0.5° C. (31° F.) using an ice bath. Vacuum filtration was performed to remove the IM BNCP from the emulsion. The IM BNCP was then washed with isopropyl alcohol and air dried.
In a 500 milliliter (ml) beaker, 0.35 g of Triton® N-101 was dissolved in water. To the low surface tension water, 16.8 g NaNT was added while vigorous stirring was performed. 0.1 g 70% perchloric acid was added to the solution until the pH was about 2 to about 3. While vigorously stirring, 10 g CTCN was added to the solution, which raised the pH of the solution. Stirring was slowed and 70% perchloric acid was again added dropwise until the pH returned to about 2 to about 3, during which time CO2 evolved. Moderate stirring was continued and the solution was heated to about 79.4° C. (175° F.) while the pH was maintained at about 2-3 by the addition of perchloric acid as needed. The solution temperature was maintained at 79.4° C. (175° F.) and a pH of about 2-3 for about 0.5 hours. The solution was cooled to about 48.8° C. (120° F.) and the beaker was placed in an ice bath to cool the solution to −5° C. (23° F.). The solution remained at this temperature for one hour during which an IM BNCP precipitate formed. Vacuum filtration was performed to remove the IM BNCP precipitate from the emulsion and the precipitate particles were washed with isopropyl alcohol and air dried.
Accordingly, various embodiments of insensitive munition-type BNCP explosive material have been provided herein. The IM BNCP particles comprise a particle of BNCP encapsulated by a surface active agent or “surfactant”. The surfactant serves as a protective shell that protects the BNCP particle from mechanical shocks, fire, electrostatic discharge, and impact by shrapnel that would otherwise result in sympathetic detonation of the BNCP. Despite the presence of the surfactant shell, the BNCP particle is still capable of high-order detonation per design intent. The IM BNCP particle can be formed by colloidal or non-colloidal approaches, both of which achieve IM BNCP particles having particle diameter sizes in the range of 20 nm to about 8 μm.
While at least one exemplary embodiment has been presented in the foregoing detailed description of the invention, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment of the invention, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended claims and their legal equivalents.
| Number | Name | Date | Kind |
|---|---|---|---|
| 4093623 | Gilligan et al. | Jun 1978 | A |
| 4094879 | Bates et al. | Jun 1978 | A |
| 4270455 | Janoski | Jun 1981 | A |
| 4552598 | Lee et al. | Nov 1985 | A |
| 5831203 | Ewick | Nov 1998 | A |
| 5929368 | Ewick et al. | Jul 1999 | A |
| 6408759 | Ewick et al. | Jun 2002 | B1 |
| 6761116 | Daoud | Jul 2004 | B2 |
| 7253288 | Renz et al. | Aug 2007 | B2 |
| 20090044885 | Brisighella et al. | Feb 2009 | A1 |
| 20090044886 | Brisighella et al. | Feb 2009 | A1 |
| Entry |
|---|
| Talawar, M.B., et al. “Energetic co-ordination compounds: synthesis, characterization and thermolysis studies on bis-(5-nitro-2H-tetrazolato-N2) tetramine cobalt(III) perchlorate (BNCP) and its new transition metal (Ni/Cu/Zn) Perchlorate analogues”; Journal of Hazardous Materials, A120 (2005), p. 25-35. |
| Merson, John A. et al. “The Development of Laser Ignited Deflagration-To-Detonation Transition (DDT) Detonators and Pyrotechnic Actuators”; 1994 Joint USA-Russia Energetic Material Technology Symposium; Livermore, California, May 18-25, 1994. |
| Number | Date | Country | |
|---|---|---|---|
| 20120180914 A1 | Jul 2012 | US |
